What is that star icon on some enemies?

[Silver Smurfer]

I don't remember seeing it when i played month ago. It's not hero, it's looks different and i see it very often.

[Pythagoras]

I think it means they are Veterans.

[tomasoltis]

do they have some special stuff, equipment or skills ? Or is there any info on them ?

I saw modifiers vs veterans, but I thought it is the heroes :P

[Pythagoras]

If you kill enough you get an achievement. I think they are simply a bit stronger, but not as high as heroes. And they are not the same.

And yes, these modifiers probably are intended for these veterans.